Thread (4 messages) 4 messages, 3 authors, 2021-02-27

Re: [PATCH bpf-next] bpf: devmap: move drop error path to devmap for XDP_REDIRECT

From: Edward Cree <ecree.xilinx@gmail.com>
Date: 2021-02-17 20:16:26
Also in: bpf

On 17/02/2021 13:56, Lorenzo Bianconi wrote:
quoted hunk ↗ jump to hunk
We want to change the current ndo_xdp_xmit drop semantics because
it will allow us to implement better queue overflow handling.
This is working towards the larger goal of a XDP TX queue-hook.
Move XDP_REDIRECT error path handling from each XDP ethernet driver to
devmap code. According to the new APIs, the driver running the
ndo_xdp_xmit pointer, will break tx loop whenever the hw reports a tx
error and it will just return to devmap caller the number of successfully
transmitted frames. It will be devmap responsability to free dropped frames.
Move each XDP ndo_xdp_xmit capable driver to the new API<snip>> diff --git a/drivers/net/ethernet/sfc/tx.c b/drivers/net/ethernet/sfc/tx.c
index 1665529a7271..0c6650d2e239 100644
--- a/drivers/net/ethernet/sfc/tx.c
+++ b/drivers/net/ethernet/sfc/tx.c
@@ -412,14 +412,6 @@ netdev_tx_t __efx_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb
 	return NETDEV_TX_OK;
 }
 
-static void efx_xdp_return_frames(int n,  struct xdp_frame **xdpfs)
-{
-	int i;
-
-	for (i = 0; i < n; i++)
-		xdp_return_frame_rx_napi(xdpfs[i]);
-}
-
 /* Transmit a packet from an XDP buffer
  *
  * Returns number of packets sent on success, error code otherwise.
@@ -492,12 +484,7 @@ int efx_xdp_tx_buffers(struct efx_nic *efx, int n, struct xdp_frame **xdpfs,
 	if (flush && i > 0)
 		efx_nic_push_buffers(tx_queue);
 
-	if (i == 0)
-		return -EIO;
-
-	efx_xdp_return_frames(n - i, xdpfs + i);
-
-	return i;
+	return i == 0 ? -EIO : i;
 }
Could this be "return i ?: -EIO;"?  (I'm undecided on whether that would
 actually be better.)

Either way, have an
Acked-by: Edward Cree <ecree.xilinx@gmail.com>
for the sfc part.
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